Fuse of alpha specially responsive type for projectiles



Ap 5,. 1932. P. A. AURIOL FUSE OF A SPECIALLY RESPONSIV'E TYPE FOR PROJECTILES Fig- 7 Filed Jan. 14, 1928/2? g I V J OM. a

I z a we Paten te Apr. 5, 1932 LOUIS PAUL-ALFRED AURIOL, OF PARIS, FRANCE, ASSIGNOR'TO SOCIETE FRANCAISE DES MUNITIONE DE CHASSE, DE 'IIR ET DE GUERRE, OF PARIS, FRANCE FUSE OF A SPEGIALLY RESPONSIVE TYPE FOR PROJECTILES Application filed January 14, 1928, Serial No. 246,793, and in France January 17, 1927.

My present invention relates to fuses for artillery or aircraft projectiles, which are operated by back action or by back action and inertia, and are of a particularly responsive nature.

According to my invention, the primer is brought into contact with the striker at the time when the fuse is armed, and due to the resulting contact between the striker and the primer, before the impact takes place, I am able to construct a fuse of great sensitiveness. When the projectile meets with a light obstacle, the striker needs only move by a very small amount in order to enter the primer and cause its inflammation. I thus obviate the waste space between the striker and the primer, which is variable in the known fuses for reasons of manufacture, and such fuses will not act when the displacement of the striker is less than the said space.

It is necessary that the striker, which is to be driven back when in contact with the obstacle, should be held at the front part during the trajectory, and this is effected by the use of a spring or a pin, or by the aerodynamic action of the projectile, or by like means.

When the projectile is to be handled or transported the primer and striker are held apart by safety devices which are put out of action, when the fuse is armed, either by inertia or by centrifugal force, or by like means.

Due to the slowing up of the projectile, the primer then moves forward by the effect of the inertia of its mass, and thus makes con tact with the striker. This effect of inertia can also be increased by the use of a spring, or by employing additional masses connected with the primer.

, The appended drawings which are given by way of example show various fuse constructions according to the invention.

Fig. 1 is a longitudinal section of a fuse provided with a spring-mounted striker. Fig. 2 is a like section showing a different type in which the striker is held by a transverse pin. Fig. 3 represents a fuse in which the striker is subjected to an aerodynamic effect. Fig. 4 is a sectional view on a larger scale showing a fuse of a particularly sensitive type provided with special fastening Fig. 5 is a sectional detail of a modified construction.

In the constructional form shown in Fig. 1, the fuse comprises a main body 1 which may be screwed into the ogive head of the projectile and comprises a central chamber 15 containing the striker device; this latter consists of a striker pin 2 whose head 3 extends outwardly of the main body 1, the head being guided by a pin 4 secured to the body 1 and traversing the longitudinal slots 5 in the head 3.

A spring 6 in contact with an annular member 7 placed in the chamber 15, urges the striker 2 forwardly. In the primer holder 13 is mounted the primer 12 which is optimally covered with a thin disk 14; said primer is retained by a catch 8 whose external ends or tongues 9 are in contact with a plunger sleeve 10 mounted in the central chamber of the body 1. The fuse device is completed by the detonator 11, known per se.

The operation is as follows:

When the device is transported, a shock on the striker may displace this striker by compressing the spring 6, but the point 2 will not make contact with the primer, since the head of the striker will abut against the annular member 7.

When the shot is fired, the striker will act by inertia to compress its spring 6, and the sleeve 10 also acts by inertia to bend out the ends 9 of the catch 8, as it recedes upon the primer holder 13.

WVhen upon the trajectory, due to the reduced speed of the projectile, the spring 6 will drive forward the striker, and the primer as well as the members 13, 8 and 10 will move forward by inertia, thus making contact with the striker point 2 whereby the motion is stopped. The members 8 and 10 serve as additional masses whose inertia is added to that of the primer holder 13.

Should the speed of the projectile be suddenly reduced, when an obstacle is encountered, the pieces 8, 10, 13 effect the puncture of the disk 14, thus causing the inflammation of the fuse. A shock on the head 3 of the mo fuse will produce the same result. In this manner the fuse device will operate by back action and by inertia.

In the case of Fig. 2, the striker head 3 is connected with the body of the fuse 1 by the pin 16. A spiral piece 17 is placed between the head 3 and the outer end of the fuse body; the said spiral piece, which prevents the back motion of the striker during transportation, will be unwound by centrifugal action when leaving the cannon, and will thus drop off. The safety device for the primer 12 differs from the preceding from the fact that the said primer is slidable in the primerholder 13 and is urged forwardly by a spr1ng 18. Herein I dispense with the additional mass, so that the said disk can be made thinner or can even be eliminated if the spring 18 is weak enough.

The said fuse operates only by back action, and herein the striker head 3 will shear off the pin 16 when the head strikes an obstacle.

In the device shown in Fig. 3, the striker head 3 has the form of a concave cap whrch is pierced with apertures 19 for the admission of air, it being movable in a chamber 20 formed in the front part of the body 1. The primer 12 is movable in its holder 13. The safety device for the fuse acts by inertia as in the preceding case.

On the trajectory, the primer w1ll make contact with the striker point 2 by the sole effect of inertia due to reduction of the speed caused by the resistance of the air. The striker is moved forward by the aero-dynamic action due to air entering the chamber 20.

It is an experimental fact that in the front of a projectile, a cap-shaped or flat member free to move in a cavity, open before and closed behind, it is impelled forward.

This action results from the movements of the air which takes place in the neighborhood of the point.

To permit this action in the front of a projectile, it is necessary that:

The joint between the cap-shaped member and the cavity which contains it must not be tight, there must be either a diametrical play, either holes in the cap-shaped member, 1n order that the pressure raises under the capshaped member by the entering of air with compression.

The cavity must be closed behind, or else there would be a continuous movement of air from the front to the back, which would apply the cap-shaped member in the bottom of 1ts lodging.

These two conditions are illustrated in Figures 3 and 4.

In the fuses of Figures 1 and 2, where the joint between the cap-shaped member and the cavity is tight, the moving of the air would drive back the striker 3, and it is necessary to hold it in the front, either by a spring 6 or a pin 16.

During the movement of the projectile on the trajectory, the striker remains in an outward position.

The members surrounding the primer (for example: 8, 10, 13, 14) are always screened from the aerodynamic action because they are in a rear cavity communicating with the room of the striker by only a narrow pipe guiding the point 2. The air contained in this rear cavity is in a static equilibrium with the compressed air contained under the head 3 of the striker. The arming members are only subjected to the forces resulting from the rotation and the ununiform translation.

The said fuse operates by back action, and is of a most responsive nature, since upon meeting an obstacle, the back motion of the striker will have no resistance to overcome save what is due to the aerodynamic action.

Fig. 4 shows a particular embodiment of the invention whereby I am enabled to provide a device of an inexpensive nature which will have the maximum sensitiveness and also affords perfect safety in handling.

In the case of Fig. 4, the cap-shaped member 3 which is secured to the striker point 2 is movable in the main body 1 of the fuse. When on the trajectory, the aerodynamic action will hold it in the forward position. The primer 12 is urged forwardly by the spring 25, but is held away from the striker point 2 by the fastening catches or bolts 23, these being pressed inwardly by an elastic band 24.

An annular recess 30 is formed in the body 1 adjacent the said bolts.

When the shot is fired, the rotation of the projectile obliges the bolts 23 to move outwardly and to enter the recess 30, and under the action of the spring 25 the primer 12 makes contact with the striker point 2.

As in the preceding case, the fuse is quite responsive, as the aerodynamic effect is the only obstacle to the functioning which is to be overcome.

The member 3 forming the head of the striker consists of a pressed piece of very light metal such as aluminium, duralumin metal,

magnesium alloy, or the like; a central hole is formed therein for the insertion of the striker rod 2, which has simply the shape of a pin. The members 2 and 3 are connected together by joining the edges 29 of the central hole with the head 28 of the pin by the upsetting process.

The safety device with centrifugal action formed by the bolts 23 may be completed as shown in Fig. 5 by the ring 31 which is adapted to disappear by inertia when the shot is fired. To prevent all movement of said ring during transportation, it is held by a pin 32, 1

which is sheared off at the start, thus releasing the ring 31. The said ring may also be held by a spring which is compressed when the shot is fired.

In the case of aeroplane projectiles, the

safety device may consist of a pin which is torn off when the projectile drops, or of a safety device of a known type adapted for release, to which may be added a propeller aiming device, and in all cases the elements serve to hold the primer at the rear of the apparatus during transportation, and to release it when on the trajectory.

Obviously, the said invention is not limited by the forms of construction shown in the drawings, which are given solely by way of example.

As an instance, the positions of the primer and striker may be inverted, and herein the primer is carried by the element subjected to back action, and the striker will be placed at the rear of the fuse device together with its safety parts. I may also modify the construction shown in the figures, as concerns the arrangement holding the striker at the front, and also as concerns the safety devices for the primer, the aiming parts for the same, and the means for moving forward the primer, the principal feature of the invention being the formation of a contact between the point of the striker and the primer before the impact takes place.

The percussion fuses of the known types may be converted into fuses according to the invention. The fuses of the R. Y. or the R. Y. G. types can be arranged according to Fig. 1. The arming system for the said R. Y. and R. Y. G. fuses might even be preserved. I may simply increase the length of the striker point, and increase the thickness of the disk placed upon the primer, and may also regulate the various partial lengths, or may provide a suitable longitudinal play for the primer in its recess, and in this'manner, when the projectile is upon its trajectory, the contact between the striker point and the primer disk will be assured in accordance with the invention.

I may further employ the known A. L. tapered fuses, adding thereto a safety device for the primer, and thus obtain a construction of the type shown in Fig. 2. The known fuses of the specially responsive types may be modified according to Fig. 3, and in this event I eliminate the parts which serve to arm the striker, and employ suitable safety devices for the primer.

Claims:

1. In a projectile, a fuse comprising a casing, a cap movable therein, a striking pin fixed to thecap and axially movable in the casing, a primer in the casing, yieldable means to urge the primer toward the striking pin, means engaged with the primer for holding the yieldable means normally inactive, the holding means being operable only after the projectile moves freely along its trajectory to release the primer, and thus the yieldable means to move the primer into yielding contact with the striking pin.

2. In a projectile, a fuse comprising a casing, a cap slidable in the casing, a striking pin fixed to and movable with the cap, a primer in the casing, bolts slidable transversely in the casing and having their inner ends engaged upon the primer, a spring between the primer and one end of the casing, a resilient band engaging the outer ends of the bolts to normally hold the inner ends thereof engaged on the primer and the spring under tension, said bolts being slidable in a direction to release the primer upon rotation of the projectile when it starts on its trajectory, said primer upon release being limited in its movement upon contact with the striking pin.

In testimony whereof I afiix my signature.

LOUIS PAUL ALFRED AURIOL. 

